New thinking for filth fly control: residual, non‐chemical wall spray from volcanic glass

Abstract

Filth flies are of medical and veterinary importance because of the transfer of disease organisms to animals and humans. The traditional control methods include the use of chemical insecticides. A novel mechanical insecticide made from volcanic glass and originally developed to control mosquitoes (Imergard™ WP; ImG) was investigated for control of adult grey flesh flies, Sarcophaga bullata (Parker), secondary screwworms, Cochliomyia macellaria (F.), and house flies, Musca domestica L. In a modified WHO cone test device, the time to 50% mortality (LT50) when applied at 5 g/m2 (tested at 30 °C and 50% relative humidity (rH)) was 7.1, 4.3 and 3.2 h, respectively. When knockdown was included, the LT50s were 5.5, 1.5 and 2.8 h, respectively. Application rates of 1.25 and greater g/m2 had the shortest LT50s. The time to the LT50 increased for M. domestica as rH increased, but ImG was still active at the highest rH tested of 70%. Scanning electron micrographs showed ImG was present on all body parts, unlike that for mosquitoes where it was found mostly on the lower legs. These first studies on the use of Imergard WP against flies suggest this could be an alternative method for filth fly control.

Mechanical Acaricides Active against the Blacklegged Tick, Ixodes scapularis

“…This also occurred at the LT90. The age difference in time to death might reflect a lower water permeability across the cuticle and/or the desiccation resistance of the tick in general in the older nymphs, as older nymphs may have a more developed cuticle that provides better protection against desiccation [ 17 , 32 ]. On the other hand, these results were counter-intuitive since the older ticks had a longer time since their last blood meal and might be expected to be more dehydrated than the younger ticks.…”

“…Understanding the exact mode of action will be critical to studies to improve the efficacy of these minerals. One advantage of Imergard is that it does not contain crystalline silica [ 17 ], although the levels in Celite are also considered safe.…”

“…Once mosquitoes came into contact with the mineral, they were no longer active [ 18 ], similar to what was seen in this study. Chen et al [ 17 ] concluded that filth flies exposed to Imergard died due to a disruption of water balance. In both mosquitoes and filth flies, the time to 50% mortality increased when the humidity was increased, suggesting that the mechanism of action might be different between insects and ticks.…”

“…Celite is derived from a unique species of diatomaceous earth, and Imergard is 100% expanded perlite, an alumina–silica volcanic rock. Both Celite and Imergard work as mechanical insecticides, with Imergard being effective against mosquitoes and filth flies [ 16 , 17 , 18 ] and Celite against filth flies and sand flies (Roe, unpublished) and for the control of thrips in cotton [ 19 ]. Celite, under the trade name Deadzone, was also active against A. americanum [ 20 ].…”

“…The mode of action of mechanical insecticides is thought to be physical, through the abrasion of the cuticle and/or absorption of cuticular lipids, resulting in increased water loss and desiccation [ 21 , 22 ]. Mechanical insecticides have been shown to be effective on a variety of different types of insects such as weevils, grain beetles, whiteflies, bedbugs, cockroaches, filth flies, fleas, mosquitoes, and ticks [ 16 , 17 , 20 , 23 , 24 , 25 , 26 ]. Both perlite and diatomaceous earth-based products are non-toxic to vertebrates and occur naturally [ 16 , 20 , 27 ].…”